<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        var a = {
            n: 1
        }
        var b = a
        a.x = a = {
            n: 2
        }
        console.log(a.x) // 打印结果是什么
    </script>
</body>

</html>